bio | website | |
---|---|---|
location | University of Copenhagen | |
age | 29 | |
visits | member for | 5 years, 3 months |
seen | 3 hours ago | |
stats | profile views | 8,557 |
Jan 26 |
awarded | Nice Answer |
Jan 25 |
answered | Certain signed sum over $S_n$ |
Jan 25 |
comment |
Exactness of pure functors
To be explicit, a functor which is the identity on pure objects but is not exact is given by mapping $V \stackrel f \to W$ to $\ker(f) \stackrel 0 \to \mathrm{coker}(f)$. Another possible fix than Jeremy Rickard's suggestion might be to impose the condition that the functors $\mathrm{gr}^W_i$ are exact. (This is just a suggestion, I don't know if the lemma holds under either added hypothesis.) |
Jan 22 |
answered | Isomorphism between a mapping class group and the fundamental group of a moduli space |
Jan 21 |
answered | Étale cohomology versus classical cohomology |
Jan 15 |
revised |
What is the value of this hyperelliptic Hodge-type integral?
added 31 characters in body |
Jan 14 |
revised |
What is the value of this hyperelliptic Hodge-type integral?
added 268 characters in body |
Jan 14 |
answered | What is the value of this hyperelliptic Hodge-type integral? |
Jan 14 |
answered | Mod 2 Totaro spectral sequence for non-orientable manifolds |
Jan 14 |
answered | cohomology version of Cartan-Leray spectral sequence that deduces cup product |
Jan 8 |
comment |
How large must $A$ be if $\{1, \ldots, N\} \subseteq A-A$?
Why the votes to close?? |
Jan 8 |
comment |
Reference for “multi-monoidal categories”
I believe that what you're after is Max Kelly's notion of a club; there is a club whose pseudo-algebras are precisely monoidal categories, and if you unravel the definition of being a pseudo-algebra for this club you should get what you wrote above. |
Jan 6 |
awarded | Enlightened |
Jan 6 |
awarded | Nice Answer |
Jan 3 |
reviewed | Close equivalence in simplicial category |
Jan 3 |
reviewed | Leave Open Is it possible on an elliptic curve both $x,y$ to be arbitrary large powers infinitely often? |
Dec 29 |
revised |
Unifying Geometry for Characteristic Classes
added 8 characters in body |
Dec 26 |
answered | cohomology of an intermediate extension of a local system |
Dec 21 |
comment |
Blow-ups of $\mathbb{P}^{n-3}$ and $(\mathbb{P}^1)^{n-3}$
Maybe you know this, but maybe it can be helpful. (It's not an answer.) The space $\overline M_{0,n}$ can be obtained from $\mathbf P^{n-3}$ by a sequence of blow ups, where the first step is blowing up at $(n-1)$ points in general position. This is in Kapranov, "Chow quotients of Grassmannian I". It can also be obtained by iterated blowing up of $(\mathbf P^1)^{n-3}$ where the first step is blowing up at the three points you picked. This is in Tavakol, "The Chow ring of the moduli space of curves of genus zero". |
Dec 20 |
comment |
What's so special about $1$-categories?
The general rule of thumb appears to be that the prevalence of $n$-categories is very rapidly decreasing as a function of $n$ (except for the special case $n=\infty$). Indeed, ordinary sets are vastly more common in day-to-day mathematics than categories, in the sense that an average mathematics paper will contain a significantly larger number of different sets than categories. Categories are in turn vastly more common than 2-categories, and so on. In the other direction, truth values are more common than sets. |